Voltage regulating apparatus



April 3, 1954 P. A. WALLACE VOLTAGE REGULATING APPARATUS Filed Oct; 21, 1952 INVENTOR. PH/LEMON A. WALLACE BY %W I and r HTTOR/VE Y Patented Apr. 13, 1954 VOLTAGE REGULATING APPARATUS Philemon A. Wallace, Bloomfield, N. J assignor to Bendix Aviation Corporation, Teterboro, N. J a corporation of Delaware Application October 21, 1952, Serial No. 315,872

5 Claims.

The present invention relates to dynamoelectric machines and more particularly to regulating apparatus for dynamoelectric machines.

Various systems have been used for regulating the output voltage of generators, however, if the regulating means are designed to hold the voltage within narrow limits, serious difliculty is encountered with over regulation or hunting. An oscillatory condition is set up causing the voltage to hunt around the desired value at a relatively low frequency.

The present invention overcomes the above disadvantage by providing accurate apparatus for regulating the output voltage and hunting is eliminated by filtering out the voltage variations caused by the hunting.

It is an object of the invention to provide a novel voltage regulating system.

Another object of the invention is to provide improved anti-hunting means for a voltage regulator.

Another object of the invention is to provide an improved accurate voltage regulator.

Another object of the invention is to provide an improved voltage regulator having a high degree of sensitivity and substantially free of hunting.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawing wherein one embodiment of the invention is illustrated by way of example.

In the drawing:

The single figure is a schematic showing of a system embodying the invention.

Referring to the drawing, a generator indicated generally by the numeral I is illustrated as having an exciting winding 2 and output winding 3. The exciting winding 2 is adapted to be driven by any conventional means (not shown) and is connected by slip rings 4 and 5. The slip ring 4 is connected by conductor 6 to a source of direct current which, for the purpose of illustration, is shown as a battery I. The slip ring 5 is connected by a conductor 8 to one end of a variable resistance element 9, illustrated as a carbon pile, of a voltage regulator indicated generally by the numeral II]. The other end of the element 9 is connected by conductor II to ground.

The voltage regulator I is shown diagrammatically as including an armature |2 pivoted at I3 and biased under tension of a spring M in a direction tending to decrease the resistance of former 39.

the carbon pile 9. A main electromagnetic winding I biases the armature |2 in a direction opposing the spring |4 tending to increase the resistance of the carbon pile 9.

The winding I5 is connected by conductors I6 and H across the output of a rectifier I8. The input to the rectifier I8 is connected by conductors I9 and across the winding 3 which is connected to output conductors 2| and 22. A resister 23 may be inserted in the conductor l9 to permit adjustment of the regulated voltage.

In addition to the main winding I5, a pair of trimmer windings 24 and 25 are provided to obtain more accurate control of the carbon pile 9. One end of the winding 24 is connected to one end of the winding 25 and the other end is connected by a conductor 26 to anode 21 of a dual triode 28. The other end of the winding 25 is connected by a conductor 29 to anode 30 of the dual triode 28. In addition to the anodes 21 and 30, the device 28 has cathodes 3| and 32 and control electrodes 33 and 34.

The cathodes 3| and 32 are tied together and connected by resistor 35 and conductor 36 to center tap 31 on secondary winding 38 of trans- The secondary winding 38 is connected by conductors 40 and 4| across the input of a rectifier 42. The output of the rectifier 42 is connected by conductor 43 to the junction of windings 24 and 25 thus providing anode current to the device 28. It is understood, however, that the anode current may be obtained from any conventional source such as a battery. A capacitor 44 may be connected across the rectifier 42.

The control grid 33 of the device 28 is connected by conductor 45 to one output terminal of a bridge circuit indicated generally by the numeral 46 and the control grid 34 is connected by conductor 4! to the other output terminal of the bridge circuit 45. Grid bias is obtained by means of resistors 48 and 49.

Resistor '50 and variable resistor 5| form one side of the bridge 46 with resistor 52 and voltage regulator tube 53 forming the other side thereof. The tube 53 may be a conventional gaseous device having non-linear characteristics such as a type 5651 regulator tube. One input terminal of the bridge 46 is connected by conductor 54 to center tap 55 of secondary winding 56 of the transformer 39. The secondary winding 56 is connected by conductors 51 and 58 across the input of rectifier 59. The output of the rectifier 59 is connected by conductor 60, inductance 6| and conductor 62 to the other input terminal of the bridge 46. A capacitor 63 is connected across 3 the input of the bridge 46. The inductance BI and capacitor 63 are proportional to form a filter circuit having a long time constant so that relatively low frequency changes in voltage are smoothed out and prevented from reaching the bridge 46.

In operation, the main winding 15 of the regulator I is connected by the rectifier l8 across the output of the generator I. The variable resistance 23 permits adjustment for obtaining a predetermined output voltage. The auxiliary windings 24 and 25 are opposing and equal at the predetermined output voltage.

The bridge 56 is adjusted by the resistor to be balanced at the predetermined output voltage. Upon a deviation from the output voltage, the bridge becomes unbalanced, in a direction depending upon the direction of deviation. This afiects the control grids 33 and 34 and the output of the two sections of the device 28 are no longer equal. The windings 24 and 25 have different ampere turns and the difierence therebetween affects the carbon pile to correct for the voltage error.

Any tendency of the system to over control or hunt is prevented by the filter comprising the inductance GI and capacitor 63. The values of the inductance El and capacitor 63 are such that relatively low frequency changes in voltage are smoothed out and prevented from affecting the bridge network. Thus the transient changes are effectively blocked 'out yet the steady state changes are not materially affected.

While the system has been illustrated in conjunction with an alternating current generator, it is understood that it would be applicable to a direct current machine.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangement of the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention.

What is claimed is? 1. Apparatus for use in regulating the output of a generator having an excitation winding, comprising a variable resistance element in circuit relationship with said excitation winding to control the energization thereof, a main control winding for affecting said resistance element to maintain a predetermined output voltage, apair of auxiliary windings, means including a bridge circuit for energizing said auxiliary windings in accordance with a condition of said bridge circuit, the energization of said windings being equal and opposing upon said bridge being balanced, said bridge being responsive to variations from said predetermined output voltage to aifect said auxiliary windings in accordance with said variations, and filter means in the inputsection of said bridge circuit proportioned to have a long time constant thereby preventing transient changes from affecting said bridge circuit.

2. Apparatus for use in regulating the output voltage of a generator having an excitation winding, comprising a carbon pile resistance element adapted to affect the energization of said excitation winding, a'main control winding responsive to output voltage for affecting said carbon pile element in accordance with a condition of said voltage, a pair of opposing auxiliary windings adapted to be energized equally at a predetermined voltage, means responsive to changes in output voltage from said predetermined value to affect said auxiliary windings in accordance with said changes, and filter means having a long time constant connected between said auxiliary windings and said generator output to block out transient changes from said auxiliary windings.

3. Voltage regulating means for controlling the output voltage of a generatorjcomprising a carbon pile element adapted to vary the energization of said generator, a main control winding, first circuit means for connecting said main winding across the output of said generator, a pair of auxiliary windings, one of said auxiliary windings being in aiding relationship to said main winding and the other auxiliary winding being in opposition thereto, a bridge circuit for energizing said auxiliary windings in accordance with a condition of said bridge, means-for adjusting said bridge to energize'said windings equally for a predetermined voltage, said bridge being responsive to changes in output voltage to aifect the condition thereof, and second circuit means including a filter circuit having a high impedance to low frequencies for energizing said bridge circuit from said output voltage.

4. The combination as describedin claim 3 and including amplifier means between said bridge circuit and said auxiliary windings.

5. Apparatus for use in regulating the output voltage of a generator having an exciting winding, comprising a variable resistance element for varying the energization' of said exciting winding, a main control winding responsive to said output voltage to vary said resistance element in accordance with variations in said output voltage, a pair of opposing auxiliary windings, a bridge circuit for energizing said auxiliary windings in accordance with a condition of said bridge, and means including a filter circuit having a long time constant for energizing said bridge from the output of said generator.

References Cited in the file of this pat nt UNITED STATES PATENTS I Name I Date Haas Feb. 28,1959

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